Just the one question.

I'm supposed to find the equation of an ellipse (well parametric, but you can give the answer in Cartesian if you prefer) given four points (the intercepts).

Whilst the question was painfully easy, the problem was that I just skipped the working out in my head and just put the numbers in the right places. Could someone please give me a guidance as to how to pursue this question?

I can expand on the question if you want.